The Effects of the Gut on Fruit Flies’ Lifespans

Figure 1. Researchers from McGill University have performed tests with fruit flies to verify whether gut changes could yield protection against age-based diseases.

Aging and chronic diseases are often associated with effects such as metabolic and oxidative stresses, inflammation, and mitochondrial deficiencies. Scientists have suggested that changes in organisms’ gut microbiota relate to specific gut phenotypes, while probiotics can be ingested to regulate chronic disease progression in conjunction with microbiota changes. However, more research is needed to understand how gut microbiota could be attributed to possible disease treatments and synbiotics, dietary supplements that contain combinations of probiotics. Doctor Satya Prakash and researchers from McGill University in Montreal, Canada conducted a study that analyzed how probiotics and synbiotics could extend the lifespan of the male fruit fly Drosophila melanogaster with respect to the gut-brain-axis (GBA), a communication system between the brain and the gastrointestinal tract (GIT). The study’s results would be used to understand how gut changes could affect organismal longevity.

To perform the study, the researchers first cultivated three probiotic strains — Lactobacillus plantarum, Lactobacillus fermentum, and Bifidobacteria longum — and formed synbiotics from these probiotic strains and the dried components of Triphala, an herbal supplement formed from fruits native to India. The researchers maintained a group of male D. melanogaster fruit flies within a cornmeal-sucrose-yeast media. A group of these fruit flies were fed with the developed synbiotics, while a second group was nurtured without synbiotics. During this process, the researchers analyzed metabolic changes associated with aging. Body weight changes were observed with ten male flies at a time, while glucose measurements were obtained from five independent groups. The researchers also analyzed the fruit flies’ internal conditions for oxidative stress markers, which normally detect imbalances between an organism’s reactive oxygen levels and the organism’s ability to detoxify reactive oxygen intermediates. The researchers also tested for inflammation markers within the fruit flies and removed mitochondria from five independent groups. The researchers removed mitochondria to determine activity levels within the electron transport chain (ETC), which drives the synthesis of ATP molecules in organisms.

The study’s results suggested that the synbiotics had beneficial effects on the fruit flies’ metabolic markers, as specimens fed with the Triphala synbiotic supplement lived for up to 66 days old, while control specimens lived for up to 40 days. The fruit flies exposed to synbiotics underwent more significant weight reductions when compared to those of the fruit flies without synbiotics. Inflammation markers, oxidative stress markers, and ETC activity levels were less significant in synbiotic fruit flies, thereby suggesting that the synbiotic diets were more effective at affecting fruit fly longevity. More research is needed to understand how the gut’s microbiotia specifically react with synbiotics; the resulting work, the researchers suggested, may be used to prevent chronic diseases.